1. Field of the Invention
This invention relates to the system for locating well equipment within the tubing string of a well. Within the tubing string are positioned locating nipples, each of which has an internal recess of a selected configuration. A tool, having expandable keys, is run through the tubing string. The keys have an outer configuration designed to mate with the internal recess configuration of a selected locating nipple.
2. The Prior Art
Frequently wells are designed so that one operation may be performed in any one of several locations therein. For example, a plurality of identical sliding sleeve valves may be positioned in the well. Frequently, it is desired to shift the sleeve of one such valve while not disturbing the sleeves of the other valves. To lessen the likelihood that the desired operation will be performed at the wrong location, selective locating systems for wells have been devised.
Heretofore, selective locating systems have generally included a single series of locating nipples. Each nipple in the series has an internal recess of a different configuration. A locating tool, having locator keys, would be run through the tubing string. The locator keys have an outer configuration which mates with the internal recess of a selected one of the locating nipples. Such locating systems are disclosed in U.S. Pat. No. 2,673,614 and 2,862, 564.
Deep wells require more locating positions than shallower wells. Well depth has graudally been increasing. Consequently, the number of desired locating positions within a well has also been increasing.
Additionally, more and more wells ae being equipped for use with pump down equipment. A pump down tool train must pass through a loop or curved portion of tubing prior to entry into the well. Therefore, each tool section is short. The short length required for pump down tools has limited the number of possible configurations for a locator key.
Presently, approximately 20 select positions can be arranged in a well. A single series of 20 locating nipples, each having an internal recess with a different configuration, can be positioned in the well. A locating tool is provided with 20 sets of keys. One specific set of locator keys will mate with the internal recess of a selected landing nipple. However, for some deep wells, 20 select positions is insufficient. More select locating positions are desired. Until this invention, an increased number of locating positions could not be obtained.